BAGHDAD – The U.S. military announced Sunday that 14 U.S. soldiers were killed over the past three days, including four in a single roadside bombing and one who was struck by a suicide bomber while on a foot patrol.

The blast that killed the four U.S. soldiers occurred Sunday as the troops were conducting a cordon and search operation northwest of Baghdad, according to a statement. Two other soldiers were killed and five were wounded along with an Iraqi interpreter in two separate roadside bombings Sunday, the military said.

In the boldest attack, a U.S. soldier was killed Friday after the patrol approached two suspicious men for questioning near a mosque southwest of Baghdad, and one of the suspects blew himself up. Military spokesman Maj. Webster Wright said U.S. troops also fired at the second suspect after he began acting aggressively, and the gunfire detonated his suicide vest.

“Our initial analysis is that these guys were Al-Qaida and were planning to launch attacks into Baghdad,” Wright said in an e-mailed statement.

Seven other soldiers were killed in a series of attacks across Iraq on Saturday.

Combined with the previously announced death of a U.S. soldier in central Baghdad on Friday, it was a deadly start for June. May was the third-bloodiest month since the war began in March 2003, with 127 personnel deaths reported.

A car bomb also exploded outside a U.S. base near the volatile city of Baquba, leaving a number of soldiers gasping for air and suffering from eye irritations, the military said. It did not confirm a report in the Los Angeles Times that the car was carrying chlorine canisters and said the soldiers who were sickened had been treated and returned to duty.

The attacks came days after the Pentagon announced the completion of the troop buildup ordered by President Bush in January, raising the total number of soldiers in Iraq to about 150,000. That number might still climb as more support troops move in.

The Bush administration has warned that the buildup will result in more U.S. casualties as more U.S. soldiers come into contact with enemy forces and concentrate on the streets of Baghdad and remote outposts.

Sectarian violence persisted against Iraqis as well, with a car parked near a police station by an open-air market exploding shortly after noon in the predominantly Shiite enclave of Balad Ruz, in volatile Diyala province of northeast of Baghdad. At least 10 people were killed.

Abu Hussein, a 35-year-old elementary school teacher, said the force of the explosion knocked a bag of vegetables out of his hands.

He was not injured so he helped to evacuate those who were, flooding the local hospital because they were afraid to take them to facilities in nearby Baquba, which has become an insurgent stronghold.

“I went back and forth many times to the site of the explosion to transfer the wounded with my private car,” he said. “I saw men and women rushing to the scene searching for their relatives and loved ones. One was crying `my brother,’ one was saying `my father,’ and a woman was crying `my husband.’ It was chaos.”

Gunmen at a fake checkpoint in Baquba, 35 miles north of Baghdad, also killed two passengers and wounded eight more when they opened fire on three minibuses that sought to flee from the highway trap.

At least 73 other Iraqis were killed or found dead nationwide, including 31 bullet-riddled bodies of men who were apparent victims of death squads.